1. Technical Field
The present invention pertains to improvements in the method and apparatus for providing sterile surgical saline solution in the operating theater. In particular, the invention simultaneously provides temperature controlled basins for surgical fluid and accessible integral temperature controlled storage for supplemental containers of the required liquid and is an improvement of the methods and apparatus disclosed in U.S. Pat. No. 4,393,659 (Keyes et al), U.S. Pat. No. 4,934,152 (Templeton), U.S. Pat. No. 5,163,299 (Faries, Jr. et al), U.S. Pat. No. 5,331,820 (Faries, Jr. et al), U.S. Pat. No. 5,333,326 (Faries, Jr. et al), U.S. Pat. No. 5,400,616 (Faries, Jr. et al) and the aforesaid U.S. patent application Ser. No. 08/399,976. The entire disclosures in these patents and patent applications are expressly incorporated herein.
2. Discussion of the Prior Art
Some surgical procedures require that an accessible supply of temperature controlled surgical slush be maintained for cooling organs or body parts. In some instances warmed sterile surgical saline is mixed with the slush to produce chilled sterile fluid at selectively controlled temperatures.
A surgical slush producing system having a cabinet with a heat transfer basin at its top is disclosed in U.S. Pat. No. 4,393,659 (Keyes et al). A refrigeration mechanism in the cabinet takes the form of a closed refrigeration loop including: an evaporator in heat exchange relation to the exterior of the heat transfer basin; a compressor; a condenser; and a refrigeration expansion control, all located in the cabinet. A separate product basin is configured to be removably received in the heat transfer basin and separated from the basin by spacers.
During use, the space between the product basin and the heat transfer basin is filled with a liquid such as alcohol or glycol serving as a thermal transfer medium between the two basins. A sterile sheet of material impervious to the thermal transfer medium is disposed between the product basin exterior and the liquid thermal transfer medium to preserve the sterile nature of the product basin. Surgically sterile liquid, such as sodium chloride solution, is placed in the product basin and congeals on the basin side when the refrigeration unit is activated. A scraping tool is used to remove the congealed sterile material to form slush of desired consistency in the basin.
Subsequently, U.S. Pat. No. 4,934,152 (Templeton) disclosed an improved apparatus wherein the product basin function is replaced in favor of a sterilized drape impervious to the sterile surgical liquid, the drape being made to conform to the basin and directly receive the sterile liquid. Congealed liquid is scraped from the conformed drape side to form the desired slush. The Templeton patent also discloses a system having two operating modes. In one mode the basin is cooled to a temperature below the freezing point of the sterile liquid. In the other mode the contents of the basin are heated to a temperature slightly elevated with respect to normal body temperature, typically on the order of 105.degree. F.
In a more recent improvement disclosed in U.S. Pat. No. 5,429,801 (Faries et al), a surgical slush machine is provided with two operating modes, a first mode operating in the range of -10.degree. F. to -70.degree. F. (nominally about -40.degree. F.) for rapidly bringing sterile liquid temperature down to its freezing temperature, and a second mode operating in the range of 20.degree. F. to 40.degree. F. for maintaining the basin near the freezing temperature of the medium.
Placing selectively and individually temperature controlled basins for providing surgical slush and warmed sterile liquid in close adjacency is disclosed in U.S. Pat. No. 5,333,326 (Faries et al). This arrangement allows the surgical staff to adjust the consistency of the sterile slush by the selective addition of warmed sterile solution, and further supports the availability of more than a single sterile compound as is occasionally required in some surgical procedures. What has not heretofore been readily and conveniently available has been an auxiliary supply of bottled sterile compound maintained at appropriate chilled and warmed temperatures for timely replenishment of the contents of the basins. Specifically, it is desirable to pre-chill or pre-warm the stored sterile liquid in order to reduce the time required to achieve desired temperature after the liquid is poured into the drape container. Storing additional bottles in separate warming and cooling units outside the surgical theater necessitates inefficient and time-consuming passage into and out of the operating room by otherwise better occupied medical personnel during the procedure.